Spark plug



Aug. 19 1924.

INVE/VTOR C( Z7'Z 5. 6111677080 A TTOR/VEVS Patented Aug. 19, 1924.

UNITED. STATES 1,505,817 PATENT OFFICE.

CARL S. SWAIQ'SON, OF NEW YORK, Y.

srm PLUG.

Application filed November 11, 1922. Serial No. 690,375.

' gaps so arranged and related and, sparkinsulated, to coin a term, that a plurality of the sparks will absolutely always be produced at each closing of the circuit by the timer of the like forming a part of the ignition system of the engine.

Another object of the invention is to provide a spark plug as just indicated, which will not be unduly expensive to manufacture, and which, most importantly, will strengthen rather than weaken the total sparking efficiency of the plug, by a true intensifying rather than an enfeebling of the individual sparks, and at the same time p prevent any possibility of short circuiting I the ground electrode.

parts of various electrode elements provided for establishin the various sets or pairs of of sparking points.

It has heretofore been proposed to provide a plurality of gaps betweenv a plurality of electrode elements at the sparking or inner 'end of a spark plug. It hasalso heretofore been proposed to provide a plurality of such gaps in the resence of at least one of such electrode e ements constituted as a .rod like or reduced projection from the metallic jacket of the plug, commonly called Again, it has heretofore been proposed to provide a plurality of sparking points at the sparking or inner end of a spark plug, and in combination therewith to provide sparkbafiles or insulating members or projections for spark-insulating various dissimilar pluralities of sparking points. Other investigators have gone even farther, and have provided insulating interponents serving to 'segregate or hold to one single sparking group each of several pairs of sparking points. It has heretofore also been'proposed partially to embed in the central core of insulation a pluralitypf spiral coils of conducting material havmg a protruding coil trode.

terminus or a plurality of protruding coil termini to act as one or both of-a pair of sparking points, and likewise partially to embed in such core cotter-p'in-shaped conductors with the .eye of each pin uppermost and embedded in the core; to provide a plurality of what may be termed floating. electrode elements.

I have discovered that remarkably efficient plane depending rib or wall of insulation at the bottom of the core, such wall or rib lying in a plane substantially perpendicular to the lane of the U-shaped floating electhat but one such floating electrode be used. Further, I have found that this discovery, to be carried out with best results, must be carried out in the presence of a proper design of the members, and particularly as to the total number of spark gaps employed and .the size of each such gap. It is especially important that the individual gaps do not exceed a certain permissible maximum; and likewise as to the number of gaps employed.

In the accompanying drawing, wherein a preferred embodiment of the invention according to the above discoveries is illustratively shown.

Fig. 1 is a central axial section;

Fig. 2 is a side elevation, partially broken away and partially in section,'look1ng toward the left in Fig. 1;

Fig. 3 is a side elevation of the insulation core of. Figs. 1 and 2, viewed as in, Fig. 2; and

Fig. 4 is a perspective view of the core and embedded parts with a portion of the for mer broken away at the top.

Similar reference characters refer to similar parts in the several views.

It will be seen that the spark plug illustrated includes the usual -,metal-lic jacket 5 and male nut 6, clamping in place the in sulating core 7 securely and in a compression-proof 'manner by means of the intert is quite important, I have found,

posed gaskets "8. At its protruding top the core carries a binding post 9 relative to the 4 upper end of a center electrode 10. The parts as so far described are of course merely illustrative of a conventional spark plug desi n.

It will e noted, however, that said center electrode diverges downwardly sufliciently away from the center'line of the core to project below the lower end of the stem to one side of a diametral line across the core bottom; and that said core carries integrally a dependent diametral plane wall or rib 11. This rib or wall, it will be noted, is shaped in side elevation like a truncated triangle, with the base uppermost.

Said electrode 10 provides a point 10" on one side of wall 11.

The single floating electrode employed pursuant to my discovery above discussed is indicated .at 12, and it will be seen that the same has its upper reversely bent end and the major part of its hairpin-formation embedded in the core 9 and wholl insulated from any part of center electrode 10. The lower terminal portions of electrode 12 depend below the bottom of main portion of core 7, one on each side of wall 11, to establish the sparking points 12 and 12", especlally good results being obtained when I sparking the former point is located as the terminus of a horizontally bent length 13. as shown in Fig. 1; establishing a'first spark gap at the pair of points 10 and 12.

The only other electrode member of the new combination is the ground electrode 14,

establishing a sparking point 14", and so establishing a second s ark a at the air of points 14" and 12*. g p p It will be noted that the spark gaps at 10-12, and at 12"-+14:- are each not greater, substantially, than the thickness of each electrode. element; and that only two gaps are provided, as I have found that an.

increase beyond these limits results in enfeeblement rather than intensification of the ttital. sparking or ignition efficiency. of the P g an insulating baflle such as indicated at "11, and when the electrode 12 is shaped as descrlbed and of an ohmic characteristic such as that indicated in the drawingwhere the material of the electrode is ordinary electrode metal.

Various slight changes might be made in the general form and arrangementof the parts described without departing from the when each pair of sparking points or spark gaps is segregated from another by invention, and hence I do not limit myself to the precise details'set forth, but consider myself at liberty to make such changes and alterations as' fairly fall within the spirit I and scope of the appended claims.

I claim:

1. In a spark plug having a jacket, a core of insulating material, and a center electrode partially embedded in said core, the combination of a single dependent, reduced msulating battle at the lower end of the core,

and a single substantially U-shaped float: ing electrode element having the free termini of the legs thereof protruded below the bottom of the core with one located on one side of said baflle and one on the other; said baffle being a plane wall arranged substantially diametrally across the bottom of the core and said centerelectrode is a substantially straight rod arranged eccentrically of the core axis.

2. In a spark plug having aacket, a core of insulating material, and a center electrode partially embedded in said-core, the combination of a single dependent, reduced insulating baflle at the lower end of the core, and a single substantially U-shaped floating electrode element having the free termini of the legs thereof protruded below the bottomof the core with one located on one side of said baflle and one on the other; said baflle being a plane Wall arranged substantially diametrally across the bottom of the core and defining substantially a truncated triangle in side elevation, with the base of the triangle uppermost.

3. In a'spark plug having a jacket, a core of insulating material, and a center electrode. partially embedded in'sald core, the combination of a single dependent, reduced insulating bafiiefat the lower end of the core,

and a single substantially U-shaped floating electrode element having the free termini of the legs thereof protrudedbelo'w the bottom of the core with one located on one side of said baflle and one on the other; a ground electrode being provided having a terminal point adjacent to the terminal point of one of the legsof said floating electrode, the

vterminal point of the other leg of said floating electrode being adjacent to the lower terminal point of the central electrode, said electrodes all being of the same material and of circular cross-section and 'of the same cross-sectional area, and the gap at each pair of electrode termini'being substantlally equal to the diameter of said area.

. I CARL S. SWANSON. 

